Use device labels rather than IDs in widget API

device IDs are different for each origin, so won't match up when passed
in & out of widgets. Use the label instead.

For https://github.com/vector-im/element-web/issues/23331

src/media-utils.ts

@@ -0,0 +1,23 @@
+/*
+Copyright 2022 Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export async function findDeviceByName(
+  deviceName: string
+): Promise<string | undefined> {
+  const devices = await navigator.mediaDevices.enumerateDevices();
+  const deviceInfo = devices.find((d) => d.label === deviceName);
+  return deviceInfo?.deviceId;
+}

src/room/GroupCallView.tsx

@@ -18,6 +18,7 @@ import React, { useCallback, useEffect, useState } from "react";
 import { useHistory } from "react-router-dom";
 import { GroupCall, GroupCallState } from "matrix-js-sdk/src/webrtc/groupCall";
 import { MatrixClient } from "matrix-js-sdk/src/client";
+import { logger } from "matrix-js-sdk/src/logger";
 
 import type { IWidgetApiRequest } from "matrix-widget-api";
 import { widget, ElementWidgetActions, JoinCallData } from "../widget";
@@ -31,6 +32,7 @@ import { useRoomAvatar } from "./useRoomAvatar";
 import { useSentryGroupCallHandler } from "./useSentryGroupCallHandler";
 import { useLocationNavigation } from "../useLocationNavigation";
 import { useMediaHandler } from "../settings/useMediaHandler";
+import { findDeviceByName } from "../media-utils";
 
 declare global {
   interface Window {
@@ -96,8 +98,30 @@ export function GroupCallView({
       const onJoin = async (ev: CustomEvent<IWidgetApiRequest>) => {
         const { audioInput, videoInput } = ev.detail
           .data as unknown as JoinCallData;
-        if (audioInput !== null) setAudioInput(audioInput);
-        if (videoInput !== null) setVideoInput(videoInput);
+
+        if (audioInput !== null) {
+          const deviceId = await findDeviceByName(audioInput);
+          if (!deviceId) {
+            logger.warn("Unknown audio input: " + audioInput);
+          } else {
+            logger.debug(
+              `Found audio input ID ${deviceId} for name ${audioInput}`
+            );
+            setAudioInput(deviceId);
+          }
+        }
+
+        if (videoInput !== null) {
+          const deviceId = await findDeviceByName(videoInput);
+          if (!deviceId) {
+            logger.warn("Unknown video input: " + videoInput);
+          } else {
+            logger.debug(
+              `Found video input ID ${deviceId} for name ${videoInput}`
+            );
+            setVideoInput(deviceId);
+          }
+        }
         await Promise.all([
           groupCall.setMicrophoneMuted(audioInput === null),
           groupCall.setLocalVideoMuted(videoInput === null),